1. Field of the Invention
This invention is for a device useful for determining the proper positioning of a dart board from a throwing line, and also for a method for the positioning.
2. State of the Art
Darts is a game played by throwing projectiles (darts) at a target scoring board (the board). The accuracy of a player's throw is effected by the distance and angle from the point of the throw to the board. Accordingly, official dart rules (e.g., those of the Americal Darts Organization, A.D.O.) specify the height of the board from the floor and the distance to the board from point of the throw.
Of these two distances, one distance is the elevation E from the standing surface, the floor, F, to the board, B. More specifically, this distance is the elevation from the hockey, H, the throwing line, to the center of the board, also called the "cork" C. The other distance is a length L from the cork C to a plane elevated from the hockey H.
In practice, the positioning of the board is typically done by first positioning the board to the proper height on a wall W by measuring from the intersection of the floor and the wall to the cork. Next, the position of the throwing line is determined either by measuring along the floor from the wall (accounting for the thickness of the board) to the hockey or by measuring from the cork to the hockey. These techniques assume that the floor is both level and perpendicular to the plane of the wall, and, accordingly, that the distance from the cork to the throwing line is the hypotenuse of a right triangle formed by the floor and the wall. For example, the A.D.O. specifies a board height of 5'8", a distance from the front surface of the board at the floor to the throwing line of 7'91/4", and a diagonal from the cork to the throwing line of 9'71/2".
A change in the distance of the throwing line of only a few inches, or even one inch, can significantly effect a player's accuracy. For perspective, the distance across the cork scoring area is about 11/4"; at a distance of 7'91/4" this becomes an angle of about 1.5.degree.. Similarly, around the outside of the scoring area is the double scoring area, two concentric circles with a distance of about 3/8" between them; at the distance of the throwing line the target area between the circles allows for an angle of about 0.5.degree.. (These measurements assume the throw is from a point which forms a line perpendicular to the plane of the game surface of the board face intermediate the borders of the scoring area.)
Precise positioning of the throwing line therefore is critical to the throw of a consistent or professional player. However, the existing system for the positioning of the board and throwing line does assumes the existence of a right angle where the floor meets the wall, and that the floor and wall be perfectly planar.
Accordingly, it would be beneficial to provide a method for more accurately positioning the board and throwing line. It also would be beneficial to provide a device to perform or assist in the performance of that method.